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Effect of breakfast on weight and energy intake: systematic review and meta-analysis of randomised controlled trials

BMJ 2019; 364 doi: (Published 30 January 2019) Cite this as: BMJ 2019;364:l42
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A GOfER diagram (Graphical Overview for Evidence Reviews) showing a visual summary of the included trials from this review.


Breakfast—the most important meal of the day?

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Re: Effect of breakfast on weight and energy intake: systematic review and meta-analysis of randomised controlled trials

Eating breakfast versus skipping breakfast: a food fight

This note concerns the recent systematic review and meta-analysis by Sievert and colleagues on the effect of breakfast on weight in healthy adults published on January 30, 2019 in BMJ (1). We, a 70 -year old physician-patient with type 2 diabetes engaged in diabetes self-management for over 20 years and her endocrinologist, find the article quite valuable to clinicians, researchers and the public at large. Available data, not always of the highest quality, lead these reviewers to the conclusion that adding breakfast to the daily meals may not be a good strategy for weight reduction in adults as it can have the opposite effect. Specifically they state that breakfast consumption, compared with skipping breakfast, raises the total intake of calories. There is a direct remedy. Make it a moderate breakfast and raise the energy expenditure to cover the added calories. We, therefore, find it necessary to add a word of caution for the vast numbers of diabetes patients always on the lookout for effective strategies for weight reduction: skipping breakfast can backfire and leave us in worse shape overall because, regardless of its impact on weight, breakfast consumption offers real metabolic benefits to people with – or at risk for - metabolic disorders, especially diabetes (2-6).

Mekary and colleagues show that skipping breakfast can increase the risk for diabetes (2). Kahleova and colleagues report that two big meals, breakfast and lunch, are better than six small meals for people with type 2 diabetes (3). Jakubowicz and coworkers find that a high-energy breakfast and low-energy dinner decrease overall daily hyperglycaemia in type 2 diabetes patients (4) and improve weight and different metabolic markers in overweight and obese women (5). The metabolic effects of breakfast are related to the hormone systems operational at the time of the meal and the fuel sources involved, along with the circadian rhythm itself. Counterregulation controls the metabolic activities of the body during the several hours of fasting through the night. Exogenous glucose is not available and the body uses other fuel sources, including free fatty acids, liver glycogen and muscle glycogen. What breakfast does is to switch the hormone system from counterregulatory hormones to the incretin-insulin system, and in 30 minutes or so exogenous glucose becomes the major fuel for the energy needs of the body. By this time free fatty acid levels have fallen and glycogen sparing is on in the liver and muscles. As a result, insulin sensitivity is the highest during the second meal of the day. (This is the so-called second-meal phenomenon (6, 7)). There are also data showing substantial diurnal variation in glucose tolerance in many diabetes patients: insulin resistance is worse in the evening, when people begin to wind down their daily activities (8, 9).

The elderly patient has been under continuous glucose monitoring (Dexcom 5) since July 2017, following two harrowing episodes of seizures brought on by impaired awareness of hypoglycaemia. With the help of CGM, under the watchful eyes of her endocrinologist, she has been testing, among other things, how the diurnal variation in glucose tolerance affects her advanced state of diabetes. She would eat identical meals for breakfast and dinner and keep all other variables, including medications, total carb count (75 gm a day) and physical activity unchanged. (The carb servings are ¾ : 2: 1: ½ : ¾ ). Although the two meals, breakfast and dinner, are identical Breakfast PPG is a lot smaller than the dinner PPG (139 vs 193 mg/dL). Glucose tolerance is high at the second meal and worse at dinner (second meal PPG ~105 mg/dL). The remedy has been to take some carb (¼ carb) from dinner and add it to the breakfast. This improves the glucose profile. Most of the carbs (4 out of 5) in the daily meals are now consumed in the earlier hours of the day and glycaemic variability is lower. This result is in line with what the three previous studies have found (3, 4, 5). This low-carb balanced meal plan is compatible with the circadian clock. A 30 min walk after breakfast and/or after lunch can burn some calories, thereby moderate the glucose surge (10). Consumption of a healthy breakfast in this manner is helpful in weight management also. The Sievert review mentions that observational studies show positive association between breakfast eating and healthy weight in those who are in the habit of making healthy lifestyle choices including not smoking, moderation in alcohol intake and add more fiber in the meals. We would like to reassure people with diabetes and those at risk for metabolic disorders that eating a balanced, healthy, moderate breakfast can offer metabolic benefits and weight loss.

Nature’s conservation laws forbid not just “free” lunches but food at all times that comes without the burden of weight gain. A practical message, therefore, to people with diabetes is this: eat a moderate, nutritious breakfast and go for a half-hour walk starting 30-minutes post-meal.

Funding: This work received no specific funding.
Duality of interest: The authors declare that there is no duality of interest associated with this manuscript.
Author's contribution: Elsamma Chacko: Literature search, study design, data collection, data interpretation; put together the first draft. Christine Signore: Endocrinologist caring for the patient, devised the treatment plan, ordered medications, CGM and lab tests, interpretation and extensive review of the various drafts of the paper.


1. Sievert K, Hussain SM, Page MJ et al. Effect of breakfast on weight and energy intake: systematic review and meta-analysis of randomized controlled trials. BMJ 2019; 364 doi:https:/

2. Mekary RA, Giovannucci E, Willett WC, van Dam RM, Hu FB. Eating patterns and type diabetes risk in men: breakfast omission, eating frequency, and snacking. Am J Clin Nutr 2012; 95(5):1182–89

3. Kahleova H, Belinova L, Malinska H et al. Eating two larger meals a day (breakfast and lunch) is more effective than six smaller meals in a reduced-energy regimen for patients with type 2 diabetes: a randomized crossover study. Diabetologia 2013; DOI:10.1007/s00125-014-3253-5

4. Jakubowicz D, Wainstein J, Ahrēn B. High-energy breakfast with low-energy dinner decreases overall daily hyperglycaemia in type 2 diabetic patients: a randomized clinical trial. Diabetologia 2015; doi:10.1007/s00125-015-3524-9

5. Jakubowicz D, Barnea M, Wainstein J, Froy O. High caloric intake at breakfast vs dinner differently influences weight loss of overweight and obese women. Obesity 2013; 21(12)

6. Jovanovic A, Gerrard J,Taylor R.The second-meal phenomenon in type 2 diabetes. Diabetes Care 2009;32:1199-1201, doi:10.2337/dc08-2196

7. Lee SH, Tura A, Mari A et al. Potentiation of the early-phase insulin response by a prior meal contributes to the second-meal phenomenon in type 2 diabetes. Am J Physiol Endocrinol Metab 2011;301: E984-E990 . DOI:10.1152/ajpendo.00244

8. Reutrakul S, Hood MM, Crowley SJ et al. Chronotype is independently associated with glycemic control in type 2 diabetes. Diabetes Care. 2018; DOI: 10. 2337/dc12-2697

9. Zimmet PZ, Wall JR, Rome R, Stimmler L, Jarrett RJ. Diurnal variation in glucose tolerance: Associated changes in plasma insulin, growth hormone, and non-esterified fatty acids. British Med Journal 1974;4: 485-491

10. Chacko E, Signore C . A physician-patient’s perspective on lowering glycemic variability - part II: the role of exercise. Diabetes Manag 2018; 8(3);057-61

Competing interests: No competing interests

21 March 2019
Elsamma Chacko
Ambulatory Care Physician
Christine Signore (Department of endocrinology, Middlesex Hospital, Middletown, CT 06457)
Connecticut Valley Hospital
1000 Silver Street, Middletown, CT 06457